Electrophotographic image forming apparatus

ABSTRACT

An electrophotographic image forming apparatus for forming an image on a recording medium includes: a light emitting member having multiple light emitting elements provided side-by-side along a direction of an axis of an electrophotographic photosensitive drum of a process cartridge removably mounted to a mounting portion to subject the drum to exposure according to image information; a light emitting member support which supports the light emitting member, and is movable between an exposure position, at which the drum is subjected to exposure, and a retracted position, at which the light emitting member is retracted from the exposure position; and a moving member configured to move the light emitting member support between the exposure position and the retracted position in a state in which the light emitting member keeps parallel to the axis of the drum.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrophotographic image formingapparatus for forming an image on a recording medium in a state in whicha process cartridge is removably mounted to an apparatus main body.

The electrophotographic image forming apparatus (hereinafter, referredto as an image forming apparatus) described herein forms an image on arecording medium by using an electrophotographic image forming process.As the image forming apparatus, there are given, for example, anelectrophotographic copying machine, an electrophotographic printer (forexample, color light emitting diode (LED) printer), a facsimile machine,and a word processor. Further, in a state in which the process cartridge(hereinafter, referred to as a cartridge) is removably mounted to animage forming apparatus main body (hereinafter, referred to as anapparatus main body), the process cartridge contributes to theelectrophotographic image forming process for forming an image on arecording medium. In the cartridge, at least one of charging means,developing means, and cleaning means each serving as process means andan electrophotographic photosensitive member (hereinafter, referred toas a photosensitive member) are integrated into a cartridge, which isremovably mounted to the apparatus main body. The charging means, thedeveloping means, and the cleaning means, which act on thephotosensitive member, are referred to as the process means. Thecartridge can be mounted to and removed from the apparatus main body bya user him/herself, and hence the user him/herself can easily performmaintenance of the apparatus main body. Further, on the recordingmedium, the image forming apparatus forms an image, and the recordingmedium includes a paper sheet and an OHP sheet.

2. Description of the Related Art

Conventionally, there is known an image forming apparatus using an LEDunit for subjecting a photosensitive member of a cartridge to exposure(Japanese Patent Application Laid-Open No. 2002-182539). The imageforming apparatus includes a slide frame slidingly movable with respectto an apparatus main body. The slide frame bears multiple cartridges, anintermediate transfer member, and an LED frame provided with the LEDunit. The LED frame is pivotably supported on the slide frame, and isarranged on the multiple cartridges. When a cartridge is replaced, theslide frame is pulled out from the apparatus main body. The LED frame onthe slide frame is manually pivoted upward. The cartridge to be removedis pulled out of the slide frame upward. Then, a cartridge to be mountedis mounted to the slide frame. The LED frame is manually pivoteddownward to be arranged on the cartridges. The slide frame is pushedinto the apparatus main body. The cartridge is replaced in theabove-mentioned procedure.

In the conventional image forming apparatus, the LED frame having theLED unit is pivotably attached to the apparatus main body (the slideframe). Therefore, a conventional technology requires a space to pivotthe LED frame. In this context, in order to pivot the LED frame when acartridge is replaced, it has been conceived to pull out the LED frameto the outside of the apparatus main body.

SUMMARY OF THE INVENTION

An object of the present invention is therefore to provide anelectrophotographic image forming apparatus capable of moving a lightemitting member support between an exposure position and a retractedposition within a smaller space in comparison with a configuration inwhich the light emitting member support is pivoted. Another object ofthe present invention is to provide an electrophotographic image formingapparatus capable of making effective use of a space in the apparatusmain body because a smaller space suffices for moving the light emittingmember between the exposure position and the retracted position incomparison with a case of pivoting the light emitting member support.

In order to achieve the above-mentioned objects, the present inventionprovides an electrophotographic image forming apparatus for forming animage on a recording medium in a state in which a process cartridge,which has an electrophotographic photosensitive drum and process meansfor acting on the electrophotographic photosensitive drum, is removablymounted to an apparatus main body, the electrophotographic image formingapparatus including: a mounting portion to which the process cartridgeis removably mounted, the mounting portion being provided in theapparatus main body; a light emitting member having multiple lightemitting elements which are provided side-by-side along a direction ofan axis of the electrophotographic photosensitive drum of the processcartridge mounted to the mounting portion, and which emit lightaccording to image information in order to subject theelectrophotographic photosensitive drum to exposure according to theimage information; a light emitting member support configured to supportthe light emitting member, the light emitting member support beingmovable between an exposure position, at which the light emittingelements emit the light to subject the electrophotographicphotosensitive drum to the exposure, and a retracted position, at whichthe light emitting member is retracted from the exposure position; and amoving member configured to move the light emitting member supportbetween the exposure position and the retracted position in a state inwhich the light emitting member keeps parallel to the axis of theelectrophotographic photosensitive drum.

According to the present invention, in comparison with the configurationin which the light emitting member support is pivoted, it is possible tomove the light emitting member support between the exposure position andthe retracted position within a smaller space.

According to the present invention, it is possible to make effective useof a space in the apparatus main body because a smaller space sufficesfor moving the light emitting member support between the exposureposition and the retracted position in comparison with a case ofpivoting the light emitting member support.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C are sectional views of an apparatus main bodyaccording to an embodiment of the present invention.

FIG. 2 is a perspective view of the apparatus main body according to theembodiment of the present invention.

FIGS. 3A and 3B are perspective views of a process cartridge accordingto the embodiment of the present invention.

FIG. 4 is a perspective view of a penetrating and retracting deviceaccording to the embodiment of the present invention.

FIGS. 5A and 5B are front views of the penetrating and retracting deviceaccording to the embodiment of the present invention.

FIG. 6 is a plan view of interlocking means according to the embodimentof the present invention.

FIG. 7 is a perspective view of a light emitting member.

DESCRIPTION OF THE EMBODIMENT

Hereinafter, an embodiment of the present invention will be describedwith reference to the attached drawings.

(Electrophotographic Image Forming Apparatus)

A color electrophotographic image forming apparatus (hereinafter,referred to as an image forming apparatus) P, to which the embodiment ofthe present invention is applied, will be described. The image formingapparatus P is a full-color LED printer of a four color type. FIGS. 1A,1B, and 1C are sectional views of an apparatus main body (hereinafter,referred to as a main body) 100 of the image forming apparatus P. FIG. 2is a perspective view of the main body 100. In FIG. 2, there is opened afront door (an openable and closable member or an operating member) 102for opening and closing an opening portion 110 provided in the main body100. A process cartridge 30 and developing cartridges 5 are movedthrough the opening portion 110 when the process cartridge 30 and thedeveloping cartridges 5 are mounted to or removed from the main body100. The door 102 is movable between a closed position for closing theopening portion 110 and an open position for opening the opening portion110. The main body 100 is a remainder of the image forming apparatus Pother than the developing cartridges 5 and the process cartridge 30. Themain body 100 is provided with a mounting portion 130 to which theprocess cartridge 30 is removably mounted. As described above, the mainbody 100 is provided with the opening portion 110 through which theprocess cartridge 30 passes when the process cartridge 30 is mounted tothe mounting portion 130 or removed from the mounting portion 130. FIG.1A is a sectional view of the image forming apparatus P in a state inwhich the door 102 is closed for performing an image forming operation.As illustrated in FIG. 1A, a drum-shaped electrophotographicphotosensitive member (an electrophotographic photosensitive drum,hereinafter, referred to as drum) 2 is arranged at a substantiallycenter portion of the main body 100. Around the drum 2, a chargingroller (process means) 3, a light emitting member 4, an intermediatetransfer belt 7, the developing cartridges 5 (5 a, 5 b, 5 c, and 5 d),and a cleaning device 6 are arranged. With this configuration, the mainbody 100 is reduced in size. The light emitting member 4 is arrangedbelow a rotation axis L (see FIGS. 5A and 5B) of the drum 2 in the mainbody 100. The charging roller 3 uniformly charges the drum 2. The lightemitting member 4 irradiates light onto a surface of the charged drum 2to form an electrostatic latent image on the drum 2.

The developing cartridges 5 develop and visualize the electrostaticlatent image formed on the drum 2 with powder developer (hereinafter,referred to as toner) of corresponding colors (yellow, magenta, cyan,and black). The toner image formed on the drum 2 is transferred onto theintermediate transfer belt 7. After transferring, the cleaning device 6removes the toner remaining on the drum 2.

Upon image formation, the drum 2 is first synchronized with rotation ofthe transfer belt 7, and is rotated in a direction (counterclockwisedirection) indicated by an arrow A of FIG. 1A. The transfer belt 7 isrotated in a direction (clockwise direction) indicated by arrows B ofFIG. 1A. The surface of the drum 2 is uniformly charged by the chargingroller 3. Onto the charged surface of the drum 2, light irradiation of ayellow image is performed by the light emitting member 4, and anelectrostatic latent image for yellow is formed on the drum 2. In orderto develop the electrostatic latent image for yellow, a voltage havingthe same charging polarity and substantially the same potential as thoseof the drum 2 is applied to a developing roller “d” of the developingcartridge 5 a containing yellow developer. In this way, yellow toner iscaused to adhere to the electrostatic latent image for yellow formed onthe drum 2, and thus a yellow toner image is formed. After that, avoltage having a polarity opposite to that of the toner is applied to aprimary transfer roller 8 arranged inside the transfer belt 7, and thenthe yellow toner image on the drum 2 is primarily transferred onto thetransfer belt 7. After the primary transfer of the yellow toner image isfinished in the above-mentioned way, in a similar way of forming theyellow image, the electrostatic latent image formation is performed toform each of a magenta image, a cyan image, and a black image. Theelectrostatic latent images are respectively developed by the magenta,cyan, and black developing cartridges (5 b to 5 d) to form a magentatoner image, a cyan toner image, and a black toner image. The developingcartridge 5 b contains magenta toner. The developing cartridge 5 ccontains cyan toner. The developing cartridge 5 d contains black toner.Each of the developing cartridges 5 has the developing roller “d”. Therespective toner images are sequentially transferred and superimposedonto the transfer belt 7 by the primary transfer roller 8. In themeantime, a secondary transfer roller 10 is out of contact with thetransfer belt 7. Further, in the meantime, a cleaning unit 9 is also outof contact with the transfer belt 7. Meanwhile, sheets (recordingmediums) S stacked and contained in a cassette 11 provided in a lowerportion of the main body 100 are separated one by one from the cassette11 by a sheet feeding roller 12, and are fed to a registration rollerpair 13. The registration roller pair 13 sends out the sheet S to asecondary transfer nip between the transfer belt 7 and the secondarytransfer roller 10 in timed relation to the toner images superimposed onthe transfer belt 7. At this time, the transfer roller 10 is held inpressure-contact with the transfer belt 7. The voltage having thepolarity opposite to that of the toner is applied to the transfer roller10. Four-color toner images superimposed on the transfer belt 7 arecollectively and secondarily transferred onto the surface of theconveyed sheet S. The sheet S onto which the toner images aretransferred is fed to a fixing device 14. In the fixing device 14, thesheet S is heated and pressurized, and the toner images are fixed on thesheet S. In this way, an image is formed on the sheet S. The sheet S isdischarged from the fixing device 14 to a discharging portion of anupper cover 15 provided in an upper portion of the main body 100.

(Light Emitting Member)

The light emitting member 4 (FIG. 7) has multiple light emittingelements 44 provided side-by-side along a longitudinal direction (adirection of a rotation axis L) of the drum 2 of the process cartridge30 mounted to the mounting portion 130. The longitudinal direction ofthe drum 2 is a direction orthogonal to a mounting/removing direction Xof the process cartridge 30. The light emitting elements 44 emit lightaccording to image information output from a controller 120, and subjectthe drum 2 to exposure. As the light emitting elements 44, there areused, for example, electroluminescent elements such as liquid crystalelements, semiconductor light emitting diodes (LEDs), and organicelectroluminescence elements (organic EL elements). FIG. 7 is aperspective view of the light emitting member 4. The light emittingmember 4 has a substrate 90. The substrate 90 is supported by a holder(not shown). The multiple light emitting elements 44 are providedside-by-side in line on a front side of the substrate 90. A driver IC 92is provided on a back side of the substrate 90. The light emittingmember 4 is arranged along the longitudinal direction of the drum 2.With this configuration, the light emitting elements 44 are arrangedalong the longitudinal direction of the drum 2. The light emittingelements 44 are electrically connected to the driver IC 92. The driverIC 92 controls a light emitting operation of the light emitting elements44. The substrate 90 is connected to the controller 120 of the main body100 through a flexible flat cable (FFC) 21. The controller 120 isprovided inside the apparatus main body. The driver IC 92 performs thelight emitting operation of the light emitting elements 44 in responseto an image information signal output from the controller 120. A SELFOC(registered trademark) lens 98 is bonded to the light emitting elements44. A surface 98 a of the lens 98 on a side on which the drum 2 isprovided is flat. The lens 98 condenses the light emitted from the lightemitting elements 44 and forms an image on the drum 2. At an exposureposition LP (see FIGS. 1A and 5A) at which the light emitting elements44 emit the light and subject the drum 2 to exposure, the light emittingmember 4 is arranged close to the drum 2. At the exposure position LP, adistance D between the surface of the drum 2 and the surface 98 a of thelens 98 of the light emitting member 4 is regulated to be thepredetermined distance.

(Process Cartridge)

FIGS. 3A and 3B are perspective views of the cartridge 30. The cartridge30 can be mounted to and removed from the main body 100 in a horizontaldirection. As illustrated in FIG. 1A, the cartridge 30 integrallyincorporates the drum 2, the charging roller 3, and the cleaning device6. In this embodiment, there is described a so-called separate-typeprocess cartridge which integrally includes the drum 2 and process meansother than developing means. However, the present invention isapplicable also to an image forming apparatus using a so-calledintegral-type process cartridge which integrally includes thephotosensitive drum and the developing means. As illustrated in FIG. 3A,the cartridge 30 includes a cartridge frame 31 integrally incorporatingthe drum 2, the charging roller 3, and the cleaning device 6. On bothside portions of the frame 31 in the longitudinal direction of the drum2, guided portions (cartridge-side guides) 32 are provided to protrudefrom the both side portions thereof, respectively. The guided portions32 extend in the direction orthogonal to the longitudinal direction ofthe drum 2. On inner sides of both side plates of the main body 100,there are provided guide portions (main-body-side guides) 112 extendinghorizontally along a moving path MP of the cartridge 30 (FIG. 1C). Theguided portions 32 are inserted in grooves of the guide portions 112.When the cartridge 30 is mounted to or removed from the main body 100,the guided portions 32 are engaged with the guide portions 112 to guidethe cartridge 30 along the mounting/removing direction X. As illustratedin FIG. 3B, in a state in which the cartridge 30 is mounted to themounting portion 130, an opening portion 33 allowing the light emittingmember 4 to penetrate is formed in a bottom of the frame 31. The openingportion 33 is provided along the direction of the axis L (thelongitudinal direction) of the drum 2. The drum 2 is exposed to theoutside through the opening portion 33. Owing to provision of theopening portion 33, it is possible to reduce an exposed area of the drum2. Thus, it is possible to reduce a risk that the light emitting member4 is contaminated with developer. Further, by allowing the lightemitting member 4 to penetrate the opening portion 33, the lightemitting member can be arranged close to a position (the exposureposition LP) optimum to subject the drum 2 to exposure. In this case,the light emitting member 4 is equally spaced apart from the drum 2along the longitudinal direction of the drum 2. Therefore, the multiplelight emitting elements 44 provided side-by-side in the light emittingmember 4 are equally spaced apart from the drum 2 along the axialdirection of the drum 2. As described above, the light emitting member 4has the multiple light emitting elements 44 which are providedside-by-side along the axial direction of the drum 2 of the cartridge 30mounted to the mounting portion 130, and which emit the light accordingto the image information for subjecting the drum 2 to exposure accordingto the image information.

A drum gear 41 for rotating the drum 2 is provided at an end portion ofthe drum 2. As illustrated in FIGS. 5A and 5B, the drum gear 41protrudes from the end portion of the cartridge 30. When the cartridge30 is mounted to the mounting portion 130, the gear 41 is engaged with adrive gear 42 provided in the main body 100. The gear 42 is driven by adrive source (not shown) provided in the main body 100 so as to rotatethe gear 41 to rotate the drum 2.

(Penetrating and Retracting Device)

FIG. 4 is a perspective view of a penetrating and retracting device (aretracting device) 1. FIGS. 5A and 5B are front views of the penetratingand retracting device 1. The penetrating and retracting device 1 has alight emitting member support 23 and a moving member 29. The lightemitting member 4 is supported through elastic members 22 (22 a and 22b) so as to be movable with respect to the light emitting member support23. Each of the elastic members 22 may be, for example, a compressionspring, an elastic foam member, or rubber. The elastic member 22 a andthe elastic member 22 b are respectively arranged on one end side andthe other end side in the longitudinal direction of the light emittingmember support along a short-side direction thereof. The elastic members22 a and 22 b are arranged between the light emitting member support 23and the light emitting member 4. Therefore, the light emitting member 4is movable in a vertical direction (perpendicular direction) withrespect to the light emitting member support 23. The light emittingmember support 23 is supported by the moving member 29 so as to bemovable with respect to a base member 24. The base member 24 is fixed tothe main body 100. Rods 25, 26, 27, and 28 constitute the moving member29. The light emitting member support 23 is supported by the base member24 through the rods 25, 26, 27, and 28 rotatably connected to the lightemitting member support 23 and the base member 24 by rotation fulcrums 1a, 1 b, 1 c, 1 d, and 1 e. A cam 17 is fixed to the rotation fulcrum 1a. The penetrating and retracting device (the retracting device) 1comprises the support 23, the moving member 29, the base member 24, andthe cam 17. The penetrating and retracting device 1 retracts the lightemitting member 4 in a direction Y perpendicular to themounting/removing direction X of the cartridge 30 (see FIG. 1B). Thatis, the penetrating and retracting device 1 can retract the lightemitting member 4 from the exposure position LP to a retracted positionRP in a direction perpendicular to a tangent (X direction) of the drum2. Further, the penetrating and retracting device 1 can make the lightemitting member 4 move from the retracted position RP to the exposureposition LP in the direction perpendicular to the tangent of the drum 2.That is, the penetrating and retracting device 1 can move the lightemitting member 4 between the retracted position RP and the exposureposition LP in a state of keeping the light emitting member 4 parallelto the longitudinal direction of the drum 2. Here, the perpendiculardirection corresponds to a right angle in terms of design, and does notneed to be a right angle in terms of mathematics. That is, theperpendicular direction described herein includes manufacturing errorand installation error, and may be practically a right angle. The lightemitting member 4 is retracted in the direction Y perpendicular to themounting/removing direction X. Therefore, in comparison with a spacenecessary for conventional retraction performed by pivoting a lightemitting member, the light emitting member 4 can be retracted from themoving path MP of the cartridge 30 within a smaller space. That is,within the smaller space, the light emitting member 4 can be movedbetween the retracted position RP and the exposure position LP. In thisembodiment, the base member 24 is provided in a direction parallel tothe mounting/removing direction of the cartridge 30. Therefore, thedirection Y perpendicular to the tangent (X direction) of the drum 2corresponds to the direction Y perpendicular to the mounting/removingdirection X of the cartridge 30. However, the present invention is notlimited to this embodiment, and the base member 24 may be arranged sothat the light emitting member 4 penetrates and retracts in thedirection Y perpendicular to the tangent (X direction) of the drum 2.The support 23 supports the light emitting member 4. The support 23 ismovable between the exposure position LP, at which the light emittingelements 44 emit the light to thereby subject the photosensitive drum 2to exposure, and the retracted position RP, at which the light emittingmember 4 is retracted from the exposure position LP.

Each of the rods 25 and 26 is attached to one side end in the short-sidedirection of the light emitting member support 23 and one side end inthe short-side direction of the base member 24. Further, each of therods 27 and 28 is attached to the other side end in the short-sidedirection of the light emitting member support 23 and the other side endin the short-side direction of the base member 24. The rotation fulcrums1 a slidably move within horizontally-elongated holes 24 a formed in thebase member 24. The rotation fulcrums 1 b slidably move withinhorizontally-elongated holes 23 a formed in the support 23. Here, thehorizontal direction corresponds to a direction horizontal to the basemember 24 (an installation surface 300 of the main body 100). When thecam 17 is moved in a direction indicated by an arrow C2 of FIG. 5A byinterlocking means described later, lower end portions of the rods 26and 28 connected to the rotation fulcrums 1 a are moved in the directionindicated by the arrow C2. The rods 25 to 28 are rotatable about therotation fulcrums 1 c. Lower end portions of the rods 25 and 27 arerotatably supported on the base member 24 by the rotation fulcrums 1 d.Upper end portions of the rods 26 and 28 are rotatably supported on thesupport 23 by the rotation fulcrums 1 e. With this configuration, whenthe cam 17 is moved in the direction indicated by the arrow C2, thesupport 23 is moved upward in the vertical direction in parallel to therotation axis L through the rotation fulcrums 1 a to 1 e and the rods 25to 28 serving as the moving member 29. Here, the vertical directioncorresponds to a direction vertical to the base member 24 (theinstallation surface 300 of the main body 100). Then, the light emittingmember 4 is inserted into the opening portion 33 of the cartridge 30.Here, inserting of the light emitting member 4 into the opening portion33 means that the light emitting member 4 penetrates from the openingportion 33 formed in an outer wall 30 c (FIGS. 1A to 1C) of thecartridge 30 into the inside of the outer wall 30 c. The opening portion33 is formed into an elongated thin shape (a slot) along thelongitudinal direction of the drum 2. The light emitting member 4 canenter the inside of the opening portion 33, and hence the light emittingmember 4 can be located at the optimum exposure position LP. Inaddition, according to this embodiment, the light emitting member 4 canbe moved between the exposure position LP and the retracted position RPin a state of keeping parallel to the longitudinal direction of the drum2. Therefore, it is possible to make the size of the opening portion 33smaller. That is, in comparison with a case where the light emittingmember 4 is pivoted to penetrate the inside of the opening portion 33,it is possible to make the size of the opening portion 33 smaller.

At this time, the surface 98 a of the lens 98 of the light emittingmember 4 is kept (supported) by a positioning mechanism (describedlater) at the predetermined distance D from the surface of the drum 2.At this time, the support 23 is located at the exposure position LP, atwhich the light emitting elements 44 emit the light according to theimage information and subject the drum 2 to exposure. The exposureposition LP is a position at which the light emitting elements 44 emitthe light to thereby subject the drum 2 to exposure, and at which themultiple light emitting elements 44 are aligned side-by-side along therotation axis L of the drum 2 and each of the multiple light emittingelements 44 is equally spaced apart from the drum 2. As the lightemitting elements 44, there are used, for example, electroluminescentelements such as liquid crystal elements, semiconductor light emittingdiodes (LEDs), and organic electroluminescence elements (organic ELelements).

In this embodiment, each of the multiple light emitting elements 44 isequally spaced apart from the drum at the exposure position LP. However,the present invention is not limited thereto. For example, when thelenses 98 respectively corresponding to the multiple light emittingelements 44 are different in dimension, distances between the multiplelight emitting elements 44 and the drum 2 are different. The distancesbetween the multiple light emitting elements 44 and the drum 2 are setso that the light emitted from the light emitting elements 44 iscondensed by the lenses 98 and an image is formed on the drum 2.Therefore, depending on specifications of the lenses 98, the multiplelight emitting elements 44 may be arranged in a curved manner so thatthe distances between the light emitting elements 44 and the drum 2 areshort at the both end portions in the direction of the rotation axis Lof the drum 2, and that the distances are long at the center portion inthe direction of the rotation axis L thereof. Or, the multiple lightemitting elements 44 may be arranged in a curved manner so that thedistances between the light emitting elements 44 and the drum 2 are longat the both end portions in the direction of the rotation axis L of thedrum 2, and that the distances are short at the center portion in thedirection of the rotation axis L thereof. The direction of the rotationaxis L corresponds to the longitudinal direction of the drum 2.

Meanwhile, when the cam 17 is moved in a direction indicated by an arrowC1 of FIG. 5B by the interlocking means described later, the rotationfulcrums 1 a fixed to the cam 17 are also moved in the directionindicated by the arrow C1. Owing to the movement of the rotationfulcrums 1 a, by an action of the moving member 29 (rods 25 to 28), thesupport 23 is moved downward in the vertical direction in parallel tothe rotation axis L. Here, the vertical direction corresponds to adirection vertical to the base member 24 (the installation surface 300of the main body 100). Then, the light emitting member 4 is moved out ofthe opening portion 33 of the cartridge 30. At this time, the support 23is located at the retracted position RP at which the light emittingmember 4 is retracted from the moving path MP (FIG. 1C) along which thecartridge 30 is moved to be mounted to or be removed from the mountingportion 130. According to this embodiment, in comparison with a largespace to pivot a conventional light emitting member, within a smallerspace in the main body 100, the support 23 can be retracted from themoving path MP of the cartridge 30. That is, the support 23 (the lightemitting member 4) can assume the exposure position LP and the retractedposition RP within the small space.

(Guide Member)

As described above, the light emitting member 4 is supported by thepenetrating and retracting device 1 through the elastic members 22 (22 aand 22 b). With this configuration, the light emitting member 4 isswingable with respect to the apparatus main body 100. The lightemitting member 4 has groove holes 4 a serving as guided members, whichare formed at both side ends in the short-side direction in both endportions in the longitudinal direction (the same as rotation axis Ldirection) of the light emitting member 4. Protrusions (guide members)23 b are respectively provided at one end portion and the other endportion in the short-side direction of the support 23 in one end portionin the longitudinal direction of the support 23. Further, protrusions(guide members) 23 b are respectively provided at one end portion andthe other end portion in the short-side direction of the support 23 inthe other end portion in the longitudinal direction thereof. The fourprotrusions 23 b are engaged with the four groove holes 4 a formed inthe light emitting member 4. Thus, swinging movement of the lightemitting member 4 in the longitudinal direction of the drum 2 is guided(regulated).

When the moving member 29 moves the support 23 from the retractedposition RP to the exposure position LP, the light emitting member 4 isbrought into contact with the cartridge 30. When the light emittingmember 4 is in contact with the cartridge 30, the elastic member 22 aprovided at the one end portion in the longitudinal direction of thesupport 23 and the elastic member 22 b provided at the other end portionare elastically deformed. The elastic members 22 a and 22 b are providedat the center in the short-side direction of the support 23 (FIG. 1A).The light emitting member 4 is pressed against the cartridge 30 byelastic forces of the elastic members 22 a and 22 b, and is moved withrespect to the support 23 due to elastic deformation of the elasticmembers 22 a and 22 b. Owing to engagement between the groove holes(guided members) 4 a and the protrusions (guide members) 23 b, themovement of the light emitting member 4 caused by the elasticdeformation of the elastic members 22 a and 22 b is guided. Therefore,even if the cartridge 30 is mounted to the mounting portion 130 in aninclined manner, the light emitting member 4 can be stably inclinedaccording to the inclination of the cartridge 30. As described above,the moving member 29 moves the support 23 such that the support ismovable between the exposure position LP and the retracted position RPin a state in which the light emitting member 4 keeps parallel to theaxis of the drum 2.

(Positioning Member)

Positioning surfaces (positioning members) 35 are provided on one endportion and the other end portion in the longitudinal direction of theopening portion 33 of the cartridge 30, respectively. A positioning hole34 a is formed in one positioning surface 35, and an elongatedpositioning hole 34 b is formed in the other positioning surface 35.Positioning bosses (positioned members) 4 b are provided on the both endportions of the light emitting member 4, respectively. A positioning pin16 a and a positioning pin 16 b are provided on an upper portion of oneboss 4 b and an upper portion of the other boss 4 b, respectively. Asillustrated in FIG. 5A, when the support 23 is located at the exposureposition LP, the pin 16 a of the light emitting member 4 is insertedinto the hole 34 a of the cartridge 30, and the pin 16 b is insertedinto the elongated hole 34 b. Owing to an engagement between the pin 16a and the hole 34 a and an engagement between the pin 16 b and theelongated hole 34 b, the light emitting member 4 is positioned withrespect to the cartridge 30. The light emitting member 4 is pressedagainst the cartridge 30 by the elastic forces of the elastic members22. The bosses 4 b of the light emitting member 4 are engaged with thepositioning surfaces 35 of the cartridge 30, and thus each of the lightemitting elements 44 is positioned so as to be equally spaced apart fromthe drum 2. Even when the cartridge 30 is mounted to the mountingportion 130 of the apparatus main body 100 in an inclined manner withinan allowable range, the light emitting member 4 can be inclinedaccording to the inclination of the cartridge 30 due to the elasticdeformation of the elastic members 22. In other words, the lightemitting member 4 can be inclined in the longitudinal direction (therotation axial direction) of the drum 2. Accordingly, the drum 2 andeach of the light emitting elements 44 can be positioned at an equalinterval. At this time, the four protrusions 23 b of the support 23 andthe four groove holes 4 a of the light emitting member 4 guide the lightemitting member 4 so as not to hamper the inclination of the lightemitting member 4 following the inclination of the cartridge 30.

The support 23 is linearly moved between the retracted position RP andthe exposure position LP while being in parallel to the base member 24(the installation surface 300 of the main body 100). That is, thesupport 23 is movable between the exposure position LP and the retractedposition RP in a state in which the light emitting member 4 keepsparallel to the longitudinal direction of the drum 2. Note that, in thecase of this embodiment, the base member 24 (the installation surface300 of the main body 100) is provided in parallel to the longitudinaldirection of the drum 2 of the cartridge 30 mounted to the mountingportion 130. When the support 23 is located at the exposure position LP,the light emitting member 4 is pressed against the cartridge 30 by theelastic forces of the elastic members 22. In a case where the cartridge30 is mounted to the mounting portion 130 in an inclined manner, theelastic member 22 a provided at the one end portion in the longitudinaldirection of the support 23 and the elastic member 22 b provided at theother end portion are elastically deformed, and thus the light emittingmember 4 is inclined according to the inclination of the cartridge 30.Therefore, it is possible to position the drum 2 of the cartridge 30 andeach of the light emitting elements 44 of the light emitting member 4 atan equal interval therebetween.

Therefore, even when the cartridge 30 is mounted on the mounting portion130 in an inclined manner, the distance D between the surface of thedrum 2 and the surface 98 a of the lens 98 of the light emitting member4 is reliably kept to be the predetermined distance. The predetermineddistance is a distance suitable to subject the drum 2 to exposure. Inthis embodiment, the predetermined distance is in a range from 2 mm to 3mm. According to this embodiment, as long as the predetermined distanceis in the above-mentioned numerical range, the drum 2 is satisfactorilysubjected to exposure through the light emission performed by the lightemitting elements 44 according to the image information. A distancemeasured from the surface of the drum 2 to the light emitting elements44 so as to cover the lens 98 is in a range from 7 mm to 8 mm. However,a lens thickness and depth of focus are changed depending on a change inthe specification of the lens 98, and hence the above-mentionedpredetermined distance is changed. Depending on the specification of thelens 98, the distance measured from the surface of the drum 2 to thelight emitting elements 44 so as to cover the lens 98 can be set to, forexample, 17 mm±0.8 mm, 10 mm±0.5 mm, 5 mm±0.3 mm, and 4 mm±0.3 mm.

(Interlocking Means)

The apparatus main body 100 includes interlocking means 40 whichautomatically moves the support 23 of the penetrating and retractingdevice 1 between the exposure position LP and the retracted position RPin association with the opening and closing operations of the front door(the openable and closable member or the operating member) 102. That is,the interlocking means 40 automatically moves the support 23 located onthe penetrating and retracting device 1 to the exposure position LP inassociation with the operation (a second operation) of closing the door102. Further, the interlocking means 40 automatically moves the support23 located on the penetrating and retracting device 1 to the retractedposition RP in association with the operation (a first operation) ofopening the door 102. Here, the door 102 is an operating member which isoperated to be opened and closed by a user when the cartridges 5 and 30are mounted to or removed from the main body 100. The interlocking means40 includes a cam spring (an elastic member) 19 serving as a biasingmember, a link 18, a link spring (an elastic member) 20 serving as abiasing member, and a link pushing portion 102 a provided on the door102 (FIG. 6). The spring 19 is coupled between the main body 100 and thecam 17. The spring 19 biases the cam 17 fixed to the rotation fulcrums 1a in a direction indicated by an arrow C1 of FIG. 6. That is, the spring19 elastically biases the support 23 on the penetrating and retractingdevice 1 to the retracted position RP. The link 18 is attached to themain body 100 so as to be movable in a direction perpendicular to themoving directions C1 and C2 of the cam 17. A forward end portion 18 a ofthe link 18 is brought into contact with the link pushing portion 102 aprovided on the door 102. A rear end portion 18 b of the link 18 isbrought into contact with the cam 17. The spring 20 is coupled betweenthe main body 100 and the link 18. The link 18 is elastically biased ina direction indicated by an arrow D1 of FIG. 6 by an elastic force ofthe spring 20. That is, when the door 102 is closed, the link 18 isbrought into contact with the link pushing portion 102 a by the elasticforce (biasing force) of the spring 20.

When a user closes the door 102 (the second operation), the link pushingportion 102 a provided on the door 102 is brought into contact with theforward end portion 18 a of the link 18. Then, the pushing portion 102 apushes the link 18 against the elastic force of the spring 20 in adirection D2 opposite to the direction indicated by the arrow D1. Whenthe link 18 is moved in the direction indicated by the arrow D2, theengagement between an inclined surface 18 c of the rear end portion 18 bof the link 18 and an inclined surface 17 a of the cam 17 (FIG. 6)causes the cam 17 and the rotation fulcrums 1 a to move in the directionindicated by the arrow C2. When the rotation fulcrums 1 a are moved inthe direction indicated by the arrow C2, the support 23 located on thepenetrating and retracting device 1 is moved to the exposure positionLP. Meanwhile, when a user opens the door 102 (the first operation), thelink pushing portion 102 a is disengaged from the forward end portion 18a of the link 18. Thus, the link 18 is moved in the direction indicatedby the arrow D1 by the elastic force of the spring 20. When the link 18is moved in the direction indicated by the arrow D1, the cam 17 and therotation fulcrums 1 a are moved in the direction indicated by the arrowC1 by the elastic force (the biasing force) of the spring 19. When thecam 17 and the rotation fulcrums 1 a are moved in the directionindicated by the arrow C1, the support 23 located on the penetrating andretracting device 1 is moved to the retracted position RP.

The operating member is not limited to the door 102, and may be, forexample, an operating lever (not shown). For example, the followingconfiguration may be adopted. Specifically, in the configuration, when auser pulls the operating lever provided on the inside of the door 102(the first operation), the pushing portion 102 a provided on theoperating lever is disengaged from the forward end portion 18 a of thelink 18. Further, when a user pushes the operating lever forward (thesecond operation), the pushing portion 102 a is engaged with the forwardend portion 18 a of the link 18. As described above, the interlockingmeans 40 moves the support 23 from the exposure position LP to theretracted position RP in association with the first operation (theoperation of opening the door 102 or the operation of pulling theoperating lever) of the operating member (the door 102 or the operatinglever). Further, the interlocking means 40 moves the support 23 from theretracted position RP to the exposure position LP in association withthe second operation of the operating member (the operation of closingthe door 102 or the operation of pushing the operating lever forward).

The interlocking means 40 is not limited to the above-mentionedconfiguration, and an appropriate configuration is applicable to theinterlocking means 40.

(Replacing Operation for Cartridge)

The developing cartridges 5 can be mounted to and removed from theapparatus main body 100 in a substantially horizontal direction (withrespect to the installation surface 300). For example, when the yellowtoner is consumed, it is necessary to replace the cartridge 5 a of thecartridges 5 of respective colors. As illustrated in FIG. 1B, a useropens the door 102 of the main body 100. A user pulls out the cartridge5 a having consumed the toner to the outside of the main body 100through the opening portion 110. A fresh cartridge 5 a filled withyellow toner is mounted to a developing cartridge mounting portion 105a, and the door 102 is closed. Thus, replacement of the cartridge 5 a iscompleted. The developing cartridges 5 b, 5 c, and 5 d of colors otherthan yellow can be replaced similarly to the yellow cartridge 5 a.

Meanwhile, when the drum 2 is replaced, a user opens the door 102 of themain body 100. Then, all the cartridges 5 a to 5 d are taken out of thedeveloping cartridge mounting portions 105 (105 a, 105 b, 105 c, and 105d) to the outside of the main body 100 (FIG. 1C). In association withthe operation of opening the door 102, the engagement between thepushing portion 102 a of the door 102 and the forward end portion 18 aof the link 18 is released. With reference to FIG. 6, the link 18 ispushed out in the direction indicated by the arrow D1 by the elasticforce (biasing force) of the spring 20. Owing to the movement of thelink 18, the cam 17 held in contact with the rear end portion 18 b ofthe link 18 is also moved in the direction indicated by the arrow C1 ofFIG. 6 by the self-weight of the light emitting member 4 and the elasticforce of the spring 19. Thus, the rotation fulcrums 1 a fixed to the cam17 are also moved in the direction indicated by the arrow C1 at the sametime. The support 23 for the light emitting member 4 is moved to theretracted position RP by the moving member 29 (as illustrated in FIG.5B). In this way, before the cartridge 30 is removed from the mountingportion 130, the moving member 29 retracts the support 23 from theexposure position LP to the retracted position RP within the main body100 in the direction Y perpendicular to the moving path MP. Asillustrated in FIG. 1B, when the support 23 is located at the retractedposition RP, the light emitting member 4 is pushed downward in thevertical direction. Further, the light emitting member 4 gets out of theopening portion 33 of the cartridge 30. Accordingly, as illustrated inFIG. 1C, the cartridge 30 can be pulled out in a removing direction X1to be removed from the main body 100. When the cartridge 30 is removedfrom the main body 100, the light emitting member 4 is located notoutside of the main body 100 but within the main body 100. Therefore, itis possible to prevent the light emitting member 4 from beingcontaminated and damaged.

The flat cable 21 electrically connects the light emitting member 4 withthe controller 120 provided in the main body 100. The cable 21 transmitsan electric signal from the controller 120 to the light emitting member4. The cable 21 is creased in advance, and hence, as illustrated in FIG.1B, the cable 21 is folded and contained below the light emitting member4 when the light emitting member 4 is moved to the retracted positionRP. The cable 21 is folded compactly, and hence the layout and designfor downsizing of the main body 100 are facilitated.

Meanwhile, in a case of mounting the cartridge 30, a user performsoperations reverse to the above-mentioned removing operations of thecartridge 30. At the time of mounting the cartridge 30, the guidedportions 32 of the cartridge 30 are inserted into the grooves of theguide portions 112 of the main body 100. The cartridge 30 ishorizontally inserted into the main body 100 through the opening portion110 of the main body 100 in a mounting direction opposite to theremoving direction X1. The cartridge 30 is positioned by a positioningportion (not shown) so as to be mounted to the mounting portion 130.Next, the developing cartridges 5 a to 5 d are inserted into the mainbody 100, and the door 102 is closed. The pushing portion 102 a providedon the door 102 is brought into contact with the forward end portion 18a of the link 18. The pushing portion 102 a pushes the link 18 in thedirection indicated by the arrow D2 against the elastic force of thespring 20 in association with the operation of closing the door 102 (thesecond operation). The rear end portion 18 b of the link 18 pushes thecam 17 in the direction indicated by the arrow C2 of FIG. 6. In thisway, a force is transmitted to the rotation fulcrums 1 a fixed to thecam 17, and the rods 26 and 28 supported by the rotation fulcrums 1 aare actuated. Thus, the moving member 29 moves the support 23 to theexposure position LP. After the cartridge 30 is mounted to the mountingportion 130, the moving member 29 moves the support 23 from theretracted position RP to the exposure position LP within the main body100 in the direction perpendicular to the moving path MP. The directionperpendicular to the moving path MP corresponds to the directionperpendicular to the base member 24 (the installation surface 300 of themain body 100). The light emitting member 4 supported by the support 23through the elastic members 22 is moved upward substantially in parallelto the base member 24. That is, the light emitting member 4 is movedbetween the retracted position RP and the exposure position LP whilekeeping the parallel state. The pin 16 a provided on the light emittingmember 4 is inserted into the hole 34 a formed in the cartridge 30, andthe pin 16 b is inserted into the elongated hole 34 b. Thus, the lightemitting member 4 is positioned with respect to the cartridge 30.Further, the light emitting member 4 is biased upward by the elasticforces of the elastic members 22, and the positioning surfaces 35 of thecartridge 30 and the positioning bosses 4 b of the light emitting member4 are brought into contact with each other. With this configuration, thedistance D between the surface 98 a of the lens 98 of the light emittingmember 4 and the surface of the drum 2 is kept to be the predetermineddistance necessary for exposure, and the lens 98 and the drum 2 arepositioned. A series of operations as described above is performed inassociation with the operation of closing the door 102 (the secondoperation), and then the series of operations is completed.

The configuration in which the light emitting member 4 is moved betweenthe retracted position RP and the exposure position LP while keepingparallel to the longitudinal direction of the drum 2 is not limited tothe above-mentioned configuration. For example, the followingconfiguration may be adopted. Specifically, in the configuration, oneend and the other end in the longitudinal direction of the lightemitting member 4 are fitted to the main-body-side guides (for example,grooves). Then, the light emitting member 4 is moved in a direction ofcoming close to the drum 2 along the guides by an elastic force of aspring. Thus, the light emitting member 4 is moved from the retractedposition RP to the exposure position LP. Further, the light emittingmember 4 is moved in a direction of moving away from the drum 2 alongthe guides with use of a lever, etc. Thus, the light emitting member 4is moved from the exposure position LP to the retracted position RP.

As described above, according to this embodiment, before the processcartridge 30 is removed from the mounting portion 130, the support 23can be moved within the main body 100 in the direction perpendicular tothe moving path MP of the cartridge 30. That is, the support 23 can bemoved between the exposure position LP and the retracted position RPwhile keeping parallel to the longitudinal direction of the drum 2.Therefore, in comparison with a case of pivoting the support 23, it ispossible to make the space necessary to move the support 23 smaller.Therefore, within the smaller space in the main body 100, the support 23can be retracted from the moving path MP of the cartridge 30. Further,according to this embodiment, when the developing cartridges 5 arereplaced, it is unnecessary to expose the light emitting member 4 to theoutside of the main body 100. Further, the light emitting member 4 isretracted downward in association with the opening and closingoperations of the door when the developing cartridges 5 are replaced.Therefore, the light emitting member 4 can remain within the main body100 also when the developing cartridges 5 are replaced. Accordingly, itis possible to prevent the light emitting member 4 from beingcontaminated and damaged. Further, it is possible to improve reliabilityof the image forming apparatus.

Further, according to this embodiment, the mounting/removing directionof the process cartridge 30 corresponds to the direction orthogonal tothe longitudinal direction of the light emitting member 4. Therefore,the cartridge 30 can be mounted and removed through the opening portion110 provided in a front surface of the main body 100. Therefore, it isunnecessary to provide an opening portion, through which the cartridge30 is mounted and removed, in a side plate of the main body 100.Accordingly, it is possible to strengthen rigidity of the main body 100.The main body 100 can keep the strong rigidity, and hence downsizing ofthe main body 100 is possible.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Applications No.2009-196727, filed Aug. 27, 2009, and No. 2009-290044, filed Dec. 22,2009, which are hereby incorporated by reference herein in theirentirety.

What is claimed is:
 1. An electrophotographic image forming apparatusfor forming an image on a recording medium in a state in which a processcartridge, which has an electrophotographic photosensitive drum andprocess means for acting on the electrophotographic photosensitive drum,is removably mounted to an apparatus main body, the electrophotographicimage forming apparatus comprising: a mounting portion to which theprocess cartridge is removably mounted, the mounting portion beingprovided in the apparatus main body; a light emitting member havingmultiple light emitting elements which are provided side-by-side along adirection of an axis of the electrophotographic photosensitive drum ofthe process cartridge mounted to the mounting portion, and which emitlight according to image information in order to subject theelectrophotographic photosensitive drum to exposure according to theimage information; a light emitting member support configured to supportthe light emitting member, the light emitting member support beingmovable between an exposure position, at which the light emittingelements emit the light to subject the electrophotographicphotosensitive drum to the exposure, and a retracted position, at whichthe light emitting member is retracted from the exposure position; and amoving member configured to move the light emitting member supportbetween the exposure position and the retracted position in a state inwhich the light emitting member keeps parallel to the axis of theelectrophotographic photosensitive drum.
 2. An electrophotographic imageforming apparatus according to claim 1, wherein the process cartridgefurther comprises a positioning member, the light emitting membercomprises a positioned member engaged with the positioning member, andwhen the light emitting member support is located at the exposureposition, the positioned member is engaged with the positioning member,and each of the light emitting elements is positioned to be equallyspaced apart from the electrophotographic photosensitive drum.
 3. Anelectrophotographic image forming apparatus according to claim 1,further comprising: an elastic member configured to support the lightemitting member to make the light emitting member movable with respectto the light emitting member support; a guided member provided on thelight emitting member; and a guide member provided on the light emittingmember support to guide the guided member, wherein the elastic member iselastically deformed by bringing the light emitting member into contactwith the process cartridge when the light emitting member support ismoved from the retracted position to the exposure position by the movingmember, and the guide member and the guided member guide the lightemitting member which is moved by elastic deformation of the elasticmember.
 4. An electrophotographic image forming apparatus according toclaim 1, further comprising: an operating member; and interlocking meansfor moving the light emitting member support from the exposure positionto the retracted position in association with a first operation of theoperating member, and for moving the light emitting member support fromthe retracted position to the exposure position in association with asecond operation of the operating member.
 5. An electrophotographicimage forming apparatus according to claim 4, further comprising: anopening portion provided in the apparatus main body, the processcartridge passing through the opening portion when the process cartridgeis mounted to the mounting portion and removed from the mountingportion; and an openable and closable member, which serves as theoperating member, and which is configured to open and close the openingportion, wherein the interlocking means moves the light emitting membersupport from the exposure position to the retracted position inassociation with an opening operation as the first operation of theopenable and closable member, and moves the light emitting membersupport from the retracted position to the exposure position inassociation with a closing operation as the second operation of theopenable and closable member.
 6. An electrophotographic image formingapparatus according to claim 1, wherein the light emitting member isarranged below the axis of the electrophotographic photosensitive drumwhen the process cartridge is mounted to the mounting portion.
 7. Anelectrophotographic image forming apparatus according to claim 1,wherein the process cartridge is provided with an opening portion intowhich the light emitting member is inserted, and wherein, when the lightemitting member support is located at the exposure position, the lightemitting member penetrates to an inside of an outer wall of the processcartridge through the opening portion.
 8. An electrophotographic imageforming apparatus according to claim 1, further comprising: a controllerprovided in the apparatus main body; and a flat cable configured toelectrically connect the controller with the light emitting member,wherein, when the light emitting member support is moved to theretracted position, the flat cable is folded below the light emittingmember.